Diagnostic value of microRNA-21 in the diagnosis of lung cancer: evidence from a meta-analysis involving 11 studies

Unraveling Therapeutic Opportunities and the Diagnostic Potential of microRNAs for Human Lung Cancer

Lung cancer is a major public health problem and a leading cause of cancer-related deaths worldwide. Despite advances in treatment options, the five-year survival rate for lung cancer patients remains low, emphasizing the urgent need for innovative diagnostic and therapeutic strategies. MicroRNAs (miRNAs) have emerged as potential biomarkers and therapeutic targets for lung cancer due to their crucial roles in regulating cell proliferation, differentiation, and apoptosis. For example, miR-34a and miR-150, once delivered to lung cancer via liposomes or nanoparticles, can inhibit tumor growth by downregulating critical cancer promoting genes. Conversely, miR-21 and miR-155, frequently overexpressed in lung cancer, are associated with increased cell proliferation, invasion, and chemotherapy resistance. In this review, we summarize the current knowledge of the roles of miRNAs in lung carcinogenesis, especially those induced by exposure to environmental pollutants, namely, arsenic and benzopyrene, which account for up to 1/10 of lung cancer cases. We then discuss the recent advances in miRNA-based cancer therapeutics and diagnostics. Such information will provide new insights into lung cancer pathogenesis and innovative diagnostic and therapeutic modalities based on miRNAs.

Relationship between diagnostic accuracy of microRNAs for NSCLC and number of combined microRNAs: an overview with meta-analysis

Objective: Several systematic reviews (SRs) have assessed the diagnostic accuracy of microRNAs (miRNAs) for NSCLC, and this overview aimed to assess the relationship between diagnostic accuracy of miRNAs for NSCLC and number of microRNAs combinations. Methods: Embase.com, PubMed, the Cochrane Library, and Web of Science were searched. The PRISMA-DTA was used for reporting quality evaluation. Meta-analysis was conducted to assess the pooled diagnostic accuracy of different miRNAs combinations, and subgroup analyses were performed based on the source of miRNA. Results: Fourteen SRs with 91 original studies were included. Three SRs had minimal reporting flaws, and 11 SRs had medium flaws. The pooled sensitivity and specificity were 0.76 and 0.80 for single miRNA, 0.80 and 0.81 for two miRNAs combined, 0.82 and 0.88 for three miRNAs combined, 0.88 and 0.92 for four miRNAs combined, 0.87 and 0.87 for five miRNAs combined, and 0.87 and 0.89 for six or more miRNAs combined. And miR-21 was mostly appeared. Subgroup analyses suggested that the serum-derived miRNA had the relatively best diagnostic value compared to other sources. Conclusions: Future studies should explore specific and serum-derived miRNAs in NSCLC and combine them to improve the diagnosis accuracy of NSCLC, which had great significance in economic efficiency.

Potential value of MicroRNA-21 as a biomarker for predicting the prognosis of patients with breast cancer: A protocol for meta-analysis and bioinformatics analysis

BACKGROUND

The latest global cancer data from 2020 shows that breast cancer has replaced lung cancer as the number one cancer in the world. Searching for new biomarkers of breast cancer has important clinical significance for early diagnosis, prediction of prognosis, and targeted therapy. MicroRNA-21 (miRNA-21) can be used as a new molecular marker for early diagnosis, prognosis, and treatment of tumors. However, the expression of miRNA-21 in breast cancer and its prognosis are not clear. Therefore, this study conducted a meta-analysis to further clarify the relationship between the expression of miRNA-21 in breast cancer and prognosis. At the same time, we carried out bioinformatics analysis to further analyze the possible molecular mechanism of miRNA-21, so as to provide potential clinical indicators for the diagnosis, treatment, and prognosis of patients.

METHODS

PubMed, Medline, Embase, Web of Science, Wanfang, Chinese Biomedical Literature Database, Chinese National Knowledge Infrastructure, and other databases were used to retrieve the published relevant literatures. Include the eligible research, extract the survival data hazard ratios and 95% confidence intervals and other information. STATA16.0 software was used for meta-analysis. Download the miRNA data of breast cancer through the Cancer Genome Atlas (TCGA) database and Gene Expression Omnibus (GEO) database. The data extracted for independent sample t test and ROC curve was drawn. OncomiR plotted the survival curve of miRNA-21 on the prognosis of breast cancer. The target genes of miRNA-21 were predicted, and the Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway were analyzed. STRING database and Cytoscape construct protein-protein interaction (PPI) network to obtain Hub gene. The correlation between the expression level of Hub gene in breast cancer and the abundance of immune cell infiltration was analyzed by TIMER database and verified by Kaplan-Meien plotter database.

RESULTS

The results of this meta-analysis will be submitted to a peer-reviewed journal for publication.

CONCLUSION

In this study, meta-analysis and bioinformatics analysis were used to further explore the prognosis, mechanism, and related pathways of miRNA-21 in breast cancer.

ETHICS AND DISSEMINATION

The private information from individuals will not be published. This systematic review also should not damage participants' rights. Ethical approval is not available. The results may be published in a peer-reviewed journal or disseminated in relevant conferences.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/R32A9.

Diagnostic Value of MicroRNA 21 in Endometrial Cancer and Benign Lesions and its Differential Expression in Relation to Clinicopathological Parameters

BACKGROUND

Endometrial cancer is one of the most common malignancies among women worldwide. Although this cancer is often diagnosed at early stages, the need for biomarkers of diagnosis remains a necessity to overcome conventional invasive procedures of diagnosis.

OBJECTIVE

In our study, we aim to investigate the diagnostic value of microRNA-21 in endometrial cancer and its relation to clinicopathological features.

METHODS

We used RT-qPCR to measure the expression of microRNA-21 in 71 tumor tissues, 53 adjacent tissues, and 54 benign lesions.

RESULTS

Our results show that microRNA-21 is a potential biomarker for endometrial cancer with an area under the receiver operating characteristic curve of 0.925 (95% CI = 0.863 - 0.964, P<0.0001). The sensitivity was 84.51% (95% CI = 74.0 - 92.0) and specificity was 86.79% (95% CI = 74.7 - 94.5). For discrimination between benign lesions and controls the AUC was 0,881 with a sensitivity of 100% (95% CI = 93.4 - 100.0) and specificity of 66.04 % (95% CI = 51.7 - 78.5), and for discriminating benign lesions from tumors the AUC was 0,750 with a sensitivity of 54.93% (95% CI = 42.7 - 66.8) and specificity of 90.74% (95% CI = 79.7 - 96.9). We also found that tumors with elevated microRNA-21 expression are of advanced FIGO stage, high histological grades, and have cervical invasion, myometrial invasion and distant metastasis.

CONCLUSION

Our findings support the important role of miR-21 as a biomarker for the diagnosis of endometrial cancer. Further studies on minimally invasive/noninvasive samples such as serum, blood, and urine are necessary to provide a better alternative to current diagnosis methods.

Association between microRNA 21 expression in serum and lung cancer: A protocol of systematic review and meta-analysis

BACKGROUND

Previous studies have reported that microRNA 21 (mRNA 21) has involved in the procedure of lung cancer (LC). However, its conclusions are still unclear. Thus, this study will try to elaborate the association between mRNA 21 expression in serum and LC.

METHODS

The electronic databases of Cochrane Library, PubMed, EMBASE, Allied and Complementary Medicine Database, WANGFANG database, and China National Knowledge Infrastructure will be retrieved from the inception to the present. All electronic databases will be searched without limitations of language and geographical location. Case-controlled studies reporting the association between mRNA 21 expression in serum and LC will be included. In addition, we will also identify other literature sources to avoid missing potential studies. All study selection, information collection, and study quality assessment will be performed by 2 independent authors. RevMan V.5.3 software and Stata V.12.0 software will be used for data synthesis and analysis.

RESULTS

This study will summarize current evidence to investigate the association between mRNA 21 expression in serum and LC.

CONCLUSION

The findings of this study will present comprehensive evidence to determine whether mRNA 21 expression in serum is relevant with LC or not.

SYSTEMATIC REVIEW REGISTRATION

INPLASY202040055.

Circulating MicroRNAs as Potential Biomarkers for Lung Cancer

Lung cancer is the number one cause of cancer-related mortality worldwide. To improve disease outcome, it is crucial to implement biomarkers into the clinics which assist physicians in their decisions regarding diagnosis, prognosis, as well as prediction of treatment response. Liquid biopsy offers an opportunity to obtain such biomarkers in a minimal invasive manner by retrieving tumor-derived material from body fluids of the patient. The abundance of circulating microRNAs is known to be altered in disease and has therefore been studied extensively as a cancer biomarker. Circulating microRNAs present a variety of favorable characteristics for application as liquid biopsy-based biomarkers, including their high stability, relatively high abundance, and presence is nearly all body fluids. Although the application of circulating microRNAs for the management of lung cancer has not entered the clinics yet, several studies showed their utility for diagnosis, prognosis, and efficacy prediction of various treatment strategies, including surgery, radio-/chemotherapy, as well as targeted therapy. To compensate for their limited tumor specificity, several microRNAs are frequently combined into microRNA panels. Moreover, the possibility to combine single microRNAs or microRNA panels with tumor imaging or other cancer-specific biomarkers has the potential to increase specificity and sensitivity and could lead to the clinical application of novel multi-marker combinations.

Blood circulating miRNAs as biomarkers of Alzheimer's disease: a systematic review and meta-analysis

Aim: It is already known that miRNAs can be differentially expressed in Alzheimer's disease (AD). We aimed to evaluate the performance of miRNAs from blood as potential biomarkers for AD. Materials & methods: MEDLINE, PubMed and Embase were searched for studies about peripheral blood miRNAs that could discriminate patients with AD from cognitively normal controls. The data regarding the specificity and sensitivity were extracted. STATA 14.0 was used to analyze the data. Results: Ten studies containing 770 AD and 664 normal controls. The analysis showed that miRNAs presented excellent diagnostic performance and the overall sensitivity was 0.80 (95% CI: 0.75-0.83), specificity was 0.83 (95% CI: 0.78-0.87) and diagnostic odds ratio was 14 (95% CI: 11-19). Subgroup analysis suggested that the Caucasian group and blood group showed a better performance in AD diagnosis and the diagnostic odds ratio was 42 and 34, respectively. Conclusion: This meta-analysis showed that miRNAs may be a promising biomarkers for AD.

Multidimensional communication of microRNAs and long non-coding RNAs in lung cancer

PURPOSE

Non-coding RNAs (ncRNAs) have been a hot topic for many years in the field of cancer research, especially miRNAs and lncRNAs. Because they play critical roles in regulating various cellular processes and are more often involved in tumorigenesis than protein-coding genes. But the cross talk between miRNAs and lncRNAs in cancer has been scarcely studied. This article aims to provide a retrospective review of the latest research on the link between miRNAs and lncRNAs in lung cancer and discusses their potential role as diagnostic biomarkers and therapeutic targets for lung cancer in clinical practice.

METHODS

We reviewed literatures about ncRNAs and lung cancer from PUBMED databases in this article.

RESULTS

As shown in our review, miRNAs and lncRNAs could represent underlying targets for diagnosis, therapy, prognosis, and drug resistence of lung cancer. By acting as ceRNAs, lncRNAs can competitively inhibit the expression levels of miRNAs, and the lncRNA/miRNA axis can contribute to tumorigenesis, metastasis, and mutidrug resistance in lung cancer via various classic signaling pathways or related proteins.

CONCLUSION

Based on present knowledge, ncRNAs may provide a novel perspective to understand the pathogenesis of lung cancer and could be candidates in screening of therapeutic targets for lung cancer.

Predictive value of microRNA let-7a expression for efficacy and prognosis of radiotherapy in patients with lung cancer brain metastasis: A case-control study

BACKGROUND

As a well-known cancer with high mortality, lung cancer has been implied to be closely associated with brain metastasis. Despite notable advances, effective treatment methods are still in urgent need. This study aims to investigate the value of serum microRNA-let-7a (miR-let-7a) expression in predicting efficacy and prognosis of radiotherapy in patients with lung cancer brain metastasis.

METHODS

To begin with, reverse transcription quantitative polymerase chain reaction (RT-qPCR) was performed for better understand of the correlation between miR-let-7a and lung cancer. Afterwards, the relationship between serum miR-let-7a expression and radiotherapy efficacy was analyzed by receiver operating characteristic curve analysis. Following successful transfection, RT-qPCR and Western blot assay were utilized for evaluating the involvement of miR-let-7a in regulation of DICER1 expression in lung cancer cell line. Then, whether miR-let-7a was implicated in proliferation and cell cycle distribution of lung cancer cells were confirmed by cell counting kit-8 assay and flow cytometry respectively.

RESULTS

Initially, it was revealed that serum miR-let-7a expression was decreased in lung cancer. Later, we found that decreased miR-let-7a displayed an unfavorable role in radiotherapy efficacy and overall survival rate of patients with lung cancer brain metastasis. After the successful transfection, the inverse relationship between miR-let-7a and DICER1 expression was uncovered. Meanwhile, biological behaviors of lung cancer cells were presented to be limited after transfection of overexpressed miR-let-7a.

CONCLUSION

Our findings demonstrated that the lower expression of miR-let-7a in patients with lung cancer brain metastasis was closely related to unfavorable efficacy and prognosis of radiotherapy, and it may be an important predictive biomarker by regulation of DICER1.

MicroRNA-21: A promising biomarker for the prognosis and diagnosis of non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the most common subtype of lung cancer worldwide. The high mortality rate of NSCLC is due to a limited number of diagnosis being made at an early stage of disease. Therefore, the development of a novel biological marker for the diagnosis and prognosis prediction of NSCLC remains urgent. Current literature shows that microRNA-21 (miRNA-21/miR-21), as an oncogenic miRNA, is involved in the growth, metastasis and apoptosis of NSCLC cells through its control of various target molecules and signaling pathways. Notably, a growing body of evidence further shows that miR-21 is closely associated with the prognosis prediction, recurrence and diagnosis of cancer patients, indicating that miR-21 may be a novel promising biomarker for the diagnosis and prognosis prediction of NSCLC. The present review aimed to provide a summary of recent findings on the associated progression toward finding a novel biomarker for NSCLC.

Diagnostic value of circulating miR-21: An update meta-analysis in various cancers and validation in endometrial cancer

MiR-21 has been identified as one of the most common proto-oncogenes. It is hypothesized that up-regulated miR-21 could be served as a potential biomarker for human cancer diagnosis. However, inconsistencies or discrepancies about diagnostic accuracy of circulating miR-21 still remain. In this sense, miR-21′s diagnostic value needs to be fully validated. In this study, we performed an update meta-analysis to estimate the diagnostic value of circulating miR-21 in various human cancers. Additionally, we conducted a validation test on 50 endometrial cancer patients, 50 benign lesion patients and 50 healthy controls. A systematical literature search for relevant articles was performed in Pubmed, Embase and Cochrane Library. A total of 48 studies from 39 articles, involving 3,568 cancer patients and 2,248 controls, were included in this meta-analysis. The overall sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR) and area under the curve (AUC) were 0.76 (0.71-0.80), 0.82 (0.79-0.85), 4.3 (3.6-5.1), 0.29 (0.24-0.35), 15 (11-20) and 0.86 (0.83-0.89), respectively. In the validation test, the expression levels of serum miR-21 were significantly higher in benign lesion patients (p = 0.003) and endometrial cancer patients (p = 0.000) compared with that of healthy controls. Endometrial cancer patients showed higher miR-21 expression levels (p = 0.000) compared with benign lesion patients. In conclusion, the meta-analysis shows that circulating miR-21 has excellent performance on the diagnosis for various cancers and the validation test demonstrates that serum miR-21 could be served as a novel biomarker for endometrial carcinoma.

Methylation and expression of RECK, P53 and RUNX genes in patients with esophageal cancer

The methylation and expression of RECK, P53 and RUNX genes in patients with esophageal cancer was investigated. In order to achieve this aim, a sample of 58 patients with esophageal cancer, treated between February 2013 and February 2014, were considered as the observation group. Additionally, a sample of 42 healthy individuals was selected as the control group. Methylation status of RECK, P53 and RUNX genes from the observation and control groups were detected by MSP. Reverse transcriptase-quantitative PCR (RT-qPCR), enzyme-linked immunosorbent assay (ELISA), western blot and immunohistochemistry were used to detect the mRNA and protein levels of RECK, P53 and RUNX in both the observation and the control groups. Results showed that the methylation rates of RECK, P53 and RUNX genes in patients with esophageal cancer were 72.4% (42/58), 1.7% (1/58) and 3.4% (2/58), respectively, which were significantly different from those in the control group [7.1% (3/42), 90.5 (38/42), and 83.3% (35/42), respectively]. The mRNA expression level of RECK is only equal to the 2.3% of that in the control group, while the mRNA expression levels of P53 and RUNX were 65.1 and 47.2 times higher than those in the control group, respectively (p<0.05). ELISA showed that RECK protein level in the observation group (0.12±0.05) µg/l, was significantly lower than the control group (3.46±0.08) µg/l (p<0.05), while, P53 and RUNX protein levels in observation group were significantly higher than that in healthy people (6.43±0.12 µg/l vs. 0.64±0.06 µg/l and 4.32±0.14 µg/l vs. 0.53±0.09 µg/l, respectively), and the results were similar to western blot. The data of immunohistochemistry showed that the proportion of RECK protein positive cells in the observation group was significantly lower than that in the control group (9.5 vs. 82.3%, P<0.05), while the proportions of P53 and RUNX protein positive cell in the observation group were significantly higher than those in the control group (78.4 vs. 11.1% and 87.3 vs. 9.06%), respectively, (P<0.05). This study concluded that, in patients with esophageal cancer, the methylation of RECK gene is increased and the expression of RECK gene is inhibited, while methylation of RUNX gene decreased and their expression was increased. This change in methylation of these genes may promote the occurrence and development of esophageal cancer.

Effects of microRNA-21 on the biological functions of T-cell acute lymphoblastic lymphoma/leukemia

Previous studies have demonstrated that microRNA-21 (miR-21) is an oncogene and is significantly upregulated in tumor tissue. However, its association with T-cell acute lymphoblastic lymphoma/leukemia (T-ALL) remains poorly understood. The aim of the present study was to investigate the effects of miR-21 on T-ALL cells by constructing Jurkat cells infected with recombinant adenovirus adv-miR-21 or adv-anti-miR-21. In addition, the target gene of miR-21 was identified by reverse transcription-quantitative polymerase chain reaction and western blotting. The results demonstrated that miR-21 expression in Jurkat cells was markedly upregulated. Furthermore, upregulating miR-21 expression in Jurkat cells promoted cell proliferation and invasion and decreased the apoptosis rate. By contrast, knockdown of miR-21 in Jurkat cells suppressed proliferation and invasion and increased the apoptosis rate. Furthermore, the results indicated that signal transducer and activator of transcription (STAT) 3 was targeted by miR-21, and that miR-21 inhibited STAT3 expression at the protein level rather than at the messenger RNA level. In conclusion, targeting the inhibition of miR-21 may be a novel therapeutic strategy for patients with T-ALL.

Correlations of microRNA:microRNA expression patterns reveal insights into microRNA clusters and global microRNA expression patterns

MicroiRNAs are genome encoded small double stranded RNAs that regulate expression of homologous mRNAs. With approximately 2500 human miRNAs and each having hundreds of potential mRNA targets, miRNA based gene regulation is quite pervasive in both development and disease. While there are numerous studies investigating miRNA:mRNA and miRNA:protein target expression correlations, there are relatively few studies of miRNA:miRNA co-expression. Here we report on our analysis of miRNA:miRNA co-expression using expression data from the miRNA expression atlas of Landgraf et al. Our analysis indicates that many, but not all, genomically clustered miRNAs are co-expressed as a single pri-miRNA transcript. We have also identified co-expression groups that have similar biological activity. Further, the non-correlative miRNAs we have uncovered have been shown to be of utility in establishing miRNA biomarkers and signatures for certain tumours and cancers.

Circulating microRNA signature as liquid-biopsy to monitor lung cancer in low-dose computed tomography screening

Liquid biopsies can detect biomarkers carrying information on the development and progression of cancer. We demonstrated that a 24 plasma-based microRNA signature classifier (MSC) was capable of increasing the specificity of low dose computed tomography (LDCT) in a lung cancer screening trial. In the present study, we tested the prognostic performance of MSC, and its ability to monitor disease status recurrence in LDCT screening-detected lung cancers.Between 2000 and 2010, 3411 heavy smokers enrolled in two screening programmes, underwent annual or biennial LDCT. During the first five years of screening, 84 lung cancer patients were classified according to one of the three MSC levels of risk: high, intermediate or low. Kaplan-Meier survival analysis was performed according to MSC and clinico-pathological information. Follow-up MSC analysis was performed on longitudinal plasma samples (n = 100) collected from 31 patients before and after surgical resection.Five-year survival was 88.9% for low risk, 79.5% for intermediate risk and 40.1% for high risk MSC (p = 0.001). The prognostic power of MSC persisted after adjusting for tumor stage (p = 0.02) and when the analysis was restricted to LDCT-detected cases after exclusion of interval cancers (p < 0.001). The MSC risk level decreased after surgery in 76% of the 25 high-intermediate subjects who remained disease free, whereas in relapsing patients an increase of the MSC risk level was observed at the time of detection of second primary tumor or metastatic progression.These results encourage exploiting the MSC test for lung cancer monitoring in LDCT screening for lung cancer.

Considering Exosomal miR-21 as a Biomarker for Cancer

Cancer is a fatal human disease. Early diagnosis of cancer is the most effective method to prevent cancer development and to achieve higher survival rates for patients. Many traditional diagnostic methods for cancer are still not sufficient for early, more convenient and accurate, and noninvasive diagnosis. Recently, the use of microRNAs (miRNAs), such as exosomal microRNA-21(miR-21), as potential biomarkers was widely reported. This initial systematic review analyzes the potential role of exosomal miR-21 as a general biomarker for cancers. A total of 10 studies involving 318 patients and 215 healthy controls have covered 10 types of cancers. The sensitivity and specificity of pooled studies were 75% (0.70–0.80) and 85% (0.81–0.91), with their 95% confidence intervals (CIs), while the area under the summary receiver operating characteristic curve (AUC) was 0.93. Additionally, we examined and evaluated almost all other issues about biomarkers, including cutoff points, internal controls and detection methods, from the literature. This initial meta-analysis indicates that exosomal miR-21 has a strong potential to be used as a universal biomarker to identify cancers, although as a general biomarker the case number for each cancer type is small. Based on the literature, a combination of miRNA panels and other cancer antigens, as well as a selection of appropriate internal controls, has the potential to serve as a more sensitive and accurate cancer diagnosis tool. Additional information on miR-21 would further support its use as a biomarker in cancer.

Retracted Article: Graphene oxide/DNA-decorated electrode for the fabrication of microRNA biosensor

A sensitive biosensor for miRNA quantification was fabricated by using a graphene oxide/DNA-decorated electrode.

Circulating microRNA-21 as a biomarker for the detection of various carcinomas: an updated meta-analysis based on 36 studies

Cancer is a class of diseases with high mortality rate, characterized by unregulated cell growth. Early diagnosis of cancer is currently the most effective method to prevent cancer development and improve the survival rate of patients. Traditional diagnostic methods such as biopsy usually provoke discomfort and unpleasant experience. Recently, microRNAs (miRNAs) were widely reported to be potential biomarkers to detect cancers without invasiveness. MicroRNA-21 (miRNA-21, miR-21) is one of the most prevalent miRNAs. This meta-analysis aims to make a comprehensive analysis of the potential role of circulating miR-21 as a biomarker in human carcinoma diagnosis. A total of 36 articles involving 2920 cancer patients and 1986 healthy controls with regard to the diagnostic value of the circulating miR-21 for cancer detection were selected from online bibliographic databases. For pooled analysis, the sensitivity, specificity, and other basic characteristics were extracted from the 36 included articles. Then, bivariate random-effects model was selected to gain pooled results. Furthermore, to explore the sources of heterogeneity, we conducted stratified and meta-regression analyses based on different race/sample groups. The pooled characteristics of all included articles were as follows: sensitivity, 0.78 (95% confidence intervals (CI), 0.73-0.82); specificity, 0.82 (95% CI, 0.79-0.86); positive likelihood ratio (PLR), 4.4 (95% CI, 3.6-5.4); negative likelihood ratio (NLR), 0.26 (95% CI, 0.21-0.33); diagnostic odds ratio (DOR), 17 (95% CI, 12-24); and area under the curve (AUC), 0.87 (95% CI, 0.84-0.90). The subgroup analyses results based on different ethnic populations revealed that the diagnostic accuracy of miR-21 tends to be higher in Asian populations than in Caucasian populations. Furthermore, another subgroup analysis performed on sample types suggested that the serum-based specimen used in cancer diagnosis appeared to be more accurate than the plasma-based specimen. Our meta-analysis shows that the circulating miR-21 may be a potential biomarker as diagnostic tool for early-stage cancer diagnosis.

The clinical utility of microRNA-21 as novel biomarker for diagnosing human cancers

With cancer being a major cause of death worldwide, microRNAs (miRNAs) have been investigated as novel and non-invasive biomarkers for cancer diagnosis. Recently, microRNA-21 (miR-21) attracts much attention for its aberrant expression and has been widely studied in various cancers. However, the inconsistent results from studies make it hard to evaluate the diagnostic value of miR-21 in cancer diagnosis, which lead us to conduct this meta-analysis. We conducted a comprehensive literature search in the Medline, Embase, PubMed, CNKI, and Web of Science before July 1, 2014. STATA 12.0 software was used for calculation and statistical analysis. The pooled sensitivity, specificity, positive and negative likelihood ratio (PLR, NLR), and diagnostic odds ratio (DOR) were used to assess the diagnostic performance of miR-21 for cancers. Seventy-three studies in 60 articles were involved in this meta-analysis, with a total of 4684 patients with cancer and 3108 controls. The overall parameters were calculated from all the included studies: sensitivity of 0.78 (95% confidence interval (CI) 0.74-0.81), specificity of 0.83 (95% CI 0.80-0.86), PLR of 4.5 (95% CI 3.8-5.4), NLR of 0.27 (95% CI 0.23-0.32); DOR of 17 (95% CI 12-23), and area under the curve (AUC) of 0.88 (95% CI 0.84-0.90). In addition, we performed subgroup analyses based on ethnicity, cancer types, and sample types. Results from subgroup analysis showed that cancer types and sample types were the sources of heterogeneity in our meta-analysis. The overall diagnostic value of miR-21 is not very high for cancer diagnosis; however, it is affected significantly by the types of cancer and specimen. MiR-21 has a relatively high diagnostic value for detecting breast cancer, and miR-21 assays based on plasma, serum, and tissue achieved relatively higher accuracy.

Circulating MicroRNA as Potential Source for Neurodegenerative Diseases Biomarkers

An increasing number of circulating micro-ribonucleic acids (microRNAs, miRNAs) have been discovered its potential as biomarkers to diagnose neurodegenerative diseases (NDs) by many researchers. However, there were obvious inconsistencies among previous studies, and thus we performed this meta-analysis to evaluate whether miRNA is an effective biomarker with high accuracy to diagnose the NDs. PubMed, MEDLINE, EMBASE, the Cochrane Library, and other related databases were used to search eligible articles. The data of sensitivity and specificity were employed to plot the summary receiver operator characteristic (SROC) curve and calculate the area under the SROC curve (AUC). I (2) test were used to estimate the heterogeneity among different studies. In addition, the possible sources of heterogeneity were further explored by subgroup analyses and meta-regression. All analyses were performed by STATA 12.0 software. In this meta-analysis, eight publications with 459 NDs patients and 340 healthy controls were included to investigate the diagnostic performance of circulating miRNAs for NDs. The overall sensitivity and specificity, positive likelihood ratio (PLR), negative likelihood ration (NLR), and diagnostic odds ratio (DOR) were 0.83 (95% confidence interval (CI) 0.77-0.88), 0.87 (95% CI 0.83-0.89), 6.2 (95% CI 4.9-7.9), 0.19 (95% CI 0.14-0.27), 33 (95% CI 20-52), and 0.91 (95% CI: 0.88-0.93), respectively. The overall SROC curve was plotted with AUC of 0.91 (95% CI 0.88-0.93), which indicated an excellent diagnostic performance of circulating miRNA for NDs. Subgroup analysis based on miRNA profile demonstrated that multiple-miRNA assay had higher diagnostic accuracy for NDs when compared with single-miRNA assay. In conclusion, the circulating miRNAs may be the potential biomarkers in the clinical diagnosis of NDs, and the diagnostic accuracy would be better by using multiple-miRNA assay. However, large-scale studies are still needed to explore the relation between the circulating miRNA dysregulation and the pathological mechanism of NDs.